RU2154810C2 - Gimballess attitude control system - Google Patents

Abstract

FIELD: gyroscopic attitude control and navigational systems. SUBSTANCE: proposed system includes angular-rate sensor unit and angular orientation determination unit, circuits "n" (n is no less than 1) of three-channel integrators and integrator synchronous restart unit connected in series. Output signals from angular-rate sensor are furnished to inputs of first integrator; these signals show present magnitudes of first integrators from angular rate components being measured; output signals of angular-rate sensor and of all integrators are furnished to input of orientation unit where parameters of orientation are calculated. All integrators have additional input for receiving signal from restart unit in order to ensure synchronous restart at zeroing all integrators at cycle time equal to scanning cycle time of angular- rate sensor. Required accuracy of generation of parameters of angular orientation under conditions of radio-frequency noise and angular vibrations of base is ensured due to use of output signals of integrators which are just increments of multiple integrals of angular-rate components being measured without use of additional smoothing of output signals of angular-rate sensor unit. EFFECT: enhanced efficiency and reliability. 2 dwg

Description

1. The technical field to which the invention relates.
The invention relates to the field of gyroscopic orientation and navigation systems for moving objects of various types and, in particular, to the class of strap-on orientation systems (BSO) in which gyroscopes are installed directly on the body of a moving object.

2. The level of technology
Orientation systems are designed to determine the angular orientation of an object relative to some basic coordinate system (SC), invariably oriented in inertial space. Usually they are part of inertial navigation systems (ANNs), but can be used independently. Known BSO, which include a block of gyroscopic sensors of angular velocity (TLS) and a computing device [Gyroscopic systems. Textbook for universities. Ed. D.S. Pelpora, 2nd ed., - M., Higher School, 1988, pp. 315-336]. The CRS unit generates three mutually orthogonal components of the absolute angular velocity along the axes associated with the SC object. The output signals of the TLS block are processed in accordance with the orientation algorithm that implements the integration of the differential kinematic equations of motion of the object in order to generate orientation parameters. Thus, the computing device performs the function of the block determining the angular orientation (block OUO).

 In recent years, widespread use of BSO built on the TLS, the output signals of which are increments of the integral from the angular velocity along the axis of sensitivity of the TLS on the cycle of his survey [Repnikov A.V., Sachkov G.P., Chernomorsky A.I. Gyroscopic systems: Textbook. allowance for aviation Universities - M., Mechanical Engineering, 1983, pp. 255-266]. (Such gyroscopes include, in particular, laser gyroscopes). It is such a BSO that is considered below as the closest analogue (prototype).

 The common features of the invention and the prototype should be considered to be the TLS unit and the TAC block installed on the object body, to the inputs of which the output signals of the TLS block are received, which are increments of the integrals from three mutually orthogonal projections of the angular velocity at the time of its polling.

 In order to achieve the required accuracy of generating the parameters of the angular orientation in the conditions of high-frequency noise of the TLS and intense angular vibration of the base in the known BSOs, it is necessary to perform additional smoothing of the output signals of the TLS in the TAC block, which leads to a significant increase in the required computational performance of the TAC block (compared to the case when high-frequency noises of DUS and vibration of the basis are absent).

3. The invention
The main task to be solved by the claimed invention is aimed at achieving the necessary accuracy of generating parameters of the angular orientation of the object under conditions of high-frequency noise of the TLS and vibration of the base without additional smoothing of the output signals of the TLS, i.e. without increasing the computing performance of the block OUO.

 This goal is achieved due to the inclusion in the BSO (in addition to the common with the prototype DCS block and the TAC block) a chain of n (n at least 1) series-connected three-channel integrators (TI) and a synchronous restart unit of integrators (SPI). The inputs of the first TI receive the output signals of the TLS unit, which are the current values of the first integrals from the measured components of the angular velocity (the signal for each of the components goes to its input of a three-channel integrator). The output signals of the TLS block and all TIs, which are increments of multiple integrals from the measured components of the angular velocity (multiples from 2 to n + 1) at the TLS polling cycle, are fed to the input of the TAC block, where the orientation parameters are calculated. All TIs have an additional input to which a signal is received from the SPI block, which ensures synchronous restart with zeroing of all integrators with a clock cycle equal to the clock cycle of the CRS block.

 The claimed technical result from the use of the invention is achieved through the use of all of the above essential features, and the more TI is used (the more n), the higher the accuracy of determining the angular orientation of the object can be achieved.

4. The list of FIG. 1 and 2
FIG. 1 and 2 illustrate the composition of the claimed device and its effectiveness in comparison with the prototype.

In FIG. Figure 1 shows the TLS block (1), a chain of n series-connected three-channel integrators (2 ₁ - 2 _n ), the OTU block (3), the SPI block (4) and the functional connections between them: the increments of the first integrals generated by the TLS block from the angular velocity components along three mutually orthogonal axes x, y, z (θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{x}}$ , θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{y}}$ , θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{z}}$ ) generated by the TI increments of multiple integrals of the components of the angular velocity (θ $\genfrac{}{}{0ex}{}{\text{2}}{\text{x}}$ , θ $\genfrac{}{}{0ex}{}{\text{2}}{\text{y}}$ , θ $\genfrac{}{}{0ex}{}{\text{2}}{\text{z}}$ ... θ $\genfrac{}{}{0ex}{}{\text{n + 1}}{\text{x}}$ , θ $\genfrac{}{}{0ex}{}{\text{n + 1}}{\text{y}}$ , θ $\genfrac{}{}{0ex}{}{\text{n + 1}}{\text{z}}$ ) and the signal generated by the SPI block of the synchronous restart of integrators with zeroing (U _cn ).

 In FIG. 2 on a logarithmic scale shows graphs of errors in determining the angular orientation for the prototype device (1) and the claimed device (2) when simulating the useful angular motion of an object, defined as a conical motion, together with high-frequency angular vibration of the base.

5. Information confirming the possibility of carrying out the invention
The inventive device shown in FIG. 1, consists of a TLS block (1), a chain of n series-connected three-channel integrators - TI (2 ₁ - 2 _n ), a block for determining the angular orientation - a TAC block (3) - and a synchronous restart unit of integrators - a TSP block (4). The output signals of the TLS block (1) and all TIs (2 ₁ - 2 _n ) are connected to the inputs of the TAC block (3), and the three inputs of the first TI (2 ₁ ) are connected to the corresponding outputs of the TLS block (1), and the additional TI inputs ( 2 ₁ - 2 _n ) are connected to the output of the SPI block (4).

 The principle of operation of the claimed device is as follows.

The inputs of the first TI (2 ₁ ) receive the output signals of the TLS block (1), which are the current values of the first integrals of the measured components of the angular velocity along three mutually orthogonal axes x, y, z (the signal for each of the components goes to its input TI) . The output signals of the TLS block (1) and all n TIs (2 ₁ - 2 _n ), which are increments of multiple integrals from the measured components of the angular velocity (multiples from 2 to n + 1) at the TLS polling cycle, are fed to the input of the TAC block (3 ), where the orientation parameters are calculated. All TIs (2 ₁ - 2 _n ) have an additional input to which a signal is supplied from the SPI block (4), which ensures synchronous restart with zeroing of all integrators with a clock cycle equal to the clock cycle of the CRS block.

In the prototype device, the integration of the three orthogonal components of the angular velocity measured by the TLS unit in the polling interval t _k , t _k + Δt (Δt is the TLS polling cycle, k = 0, 1, 2 ...) is carried out in high-resolution gyroscope electronics in a discrete form a frequency that is significantly higher than the polling frequency of the CRS unit (1 / Δt). Thus, the current values of the first integrals of the three components of the angular velocity can be read and repeatedly integrated with a high frequency. In the claimed device TI (2 ₁ - 2 _n ) can be implemented on commercially available elements of digital technology.

 The claimed technical result is achieved due to the use of special computational algorithms for determining the angular orientation of the object in the OUO block, using as an initial information increments of multiple (multiplicity j not less than 2) integrals from the angular velocity components measured by the TLS block (1) at the time of its polling. The author developed a method for synthesizing a new class of algorithms of this kind, obtained and studied specific algorithms for the cases j = 2, j = 3, and proved the effectiveness of this class of algorithms (for any j not less than 2) in comparison with the known orientation algorithms corresponding to them in complexity ( which use as an initial information only the increments of the first integrals generated by the TLS unit from the measured components of the angular velocity on the clock cycle of it) from the point of view of smoothing high-frequency components CRS output signals (noise or vibrations). The following is a summary of the main provisions and results of the development of new orientation algorithms.

According to the general methodology for the development of orientation algorithms, the increments of the parameters of the angular orientation on the step of solving the problem ΔT are expressed in terms of the coefficients of the polynomial model of the angular velocity in the interval (t _i , t _i + ΔT, i = 0,1, ...), which, in accordance with the well-known the technique is determined through the output signals of the TLS block, while the sampling frequency of the TLS - 1 / Δt in the general case can be higher than the frequency of solving the orientation problem in the TAC block - 1 / ΔT (multiple of it). The parameters of the angular velocity model are determined from the system of algebraic equations obtained for each output signal of the TLS block, so the number of coefficients that can be determined is equal to the number of output signals of the TLS block on the step of solving the problem, which is used in the algorithm.

 In accordance with the new methodology, the desired coefficients of the angular velocity model are determined from another system of algebraic equations obtained for the output signals of both the TLS block and the TI, the output signals of which are used in the algorithm, and the polling cycle of the TLS and TI block is equal to the tact of solving the orientation problem. It turns out that the estimates of the coefficients of the angular velocity model obtained in this way have the properties of least-squares estimates, i.e. possess smoothing properties.

As an example, below is the algorithm proposed by R. Miller [R. B. Miller. A new algorithm for determining orientation parameters for platform systems. Aerospace engineering, t. 2, No. 5, May 1984, pp. 127-133] - the most commonly used of the well-known algorithms that use three equally spaced time solutions to the problem of orientation of the output signals of the TLS block (θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{1}}$ , θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{2}}$ , θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{3}}$ ), and the corresponding new complexity algorithm, using three multiple integrals of the angular velocity on the step of solving the problem (θ ¹ , θ ² , θ ³ ), i.e. output signals of the TLS unit and two TIs. (θ $\genfrac{}{}{0ex}{}{\text{j}}{\text{a}}$ are the vector quantities given by the components along the x, y, z axes, the superscript characterizes the multiplicity of the integral of the angular velocity, and the bottom is the number of the tact of the TLS polling on the tact of the solution of the orientation problem. The absence of a lower index means that integration was carried out on the tact of solving the orientation problem).

R. Miller's algorithm:
Φ (t _i + ΔT) = θ ¹ + X (θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{1}}$ • θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{3}}$ ) + Yθ $\genfrac{}{}{0ex}{}{\text{1}}{\text{2}}$ • (θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{3}}$ -θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{1}}$ ), /1/
where θ ¹ = θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{1}}$ + θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{2}}$ + θ $\genfrac{}{}{0ex}{}{\text{1}}{\text{3}}$ ; X, Y are constants.

, /2/
где

коэффициенты, зависящие от ΔT.
На фиг. 2 в логарифмическом масштабе приведены графики погрешностей определения угловой ориентации в зависимости от относительной частоты (отношения частоты вибрации к частоте опроса блока ДУС) для устройства-прототипа при использовании алгоритма (1) и заявляемого устройства при использовании алгоритма (2) при имитации полезного углового движения объекта, задаваемого как коническое движение, совместно с высокочастотной угловой вибрацией основания. Как видно из приведенных кривых, новый алгоритм точнее традиционного алгоритма примерно на 2 порядка. Таким образом, необходимая точность выработки параметров угловой ориентации объекта в условиях высокочастотных шумов ДУС и вибрации основания может быть обеспечена без использования дополнительного сглаживания выходных сигналов блока ДУС, т.е. без увеличения вычислительной производительности блока ОУО.New algorithm:

, / 2 /
Where

ΔT-dependent coefficients.
In FIG. 2 on a logarithmic scale shows graphs of errors in determining the angular orientation depending on the relative frequency (the ratio of the vibration frequency to the polling frequency of the TLS unit) for the prototype device using algorithm (1) and the inventive device when using algorithm (2) when simulating useful angular movement of an object defined as a conical movement, together with high-frequency angular vibration of the base. As can be seen from the curves, the new algorithm is more accurate than the traditional algorithm by about 2 orders of magnitude. Thus, the necessary accuracy of generating the parameters of the angular orientation of the object under conditions of high-frequency noise of the TLS and vibration of the base can be ensured without using additional smoothing of the output signals of the TLS block, i.e. without increasing the computing performance of the block OUO.

Claims (1)

 A strapdown orientation system, including a three-channel block of gyroscopic angular velocity sensors and a block for determining the angular orientation, characterized in that the strapdown orientation system includes n series-connected three-channel integrators (n at least 1) and a synchronous restart unit of integrators, while the outputs of the three-channel sensor block angular velocity and all three-channel integrators are connected to the inputs of the block for determining the angular orientation, the inputs of the first three-channel integrat pa are connected to the outputs of the three-channel block of angular velocity sensors of the same name, and the additional inputs of all three-channel integrators are connected to the output of the synchronous restart unit of integrators.

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